/*
 * Copyright 2012-2020 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.boot.context.config;

import java.util.EventListener;

import org.springframework.core.env.Environment;
import org.springframework.core.env.PropertySource;

/**
 * 监听 {@link ConfigDataEnvironmentPostProcessor} 触发的 {@link Environment} 更新的 {@link EventListener}。
 *
 * @author Phillip Webb
 * @since 2.4.2
 */
public interface ConfigDataEnvironmentUpdateListener extends EventListener {

	/**
	 * 一个什么也不做的 {@link ConfigDataEnvironmentUpdateListener} 实现。
	 */
	ConfigDataEnvironmentUpdateListener NONE = new ConfigDataEnvironmentUpdateListener() {
	};

	/**
	 * 当新的 {@link PropertySource} 被添加到 {@link Environment} 时调用。
	 * @param propertySource 被添加的 {@link PropertySource}
	 * @param location 原始的 {@link ConfigDataLocation} 位置
	 * @param resource 该来源的 {@link ConfigDataResource}
	 */
	default void onPropertySourceAdded(PropertySource<?> propertySource, ConfigDataLocation location,
									   ConfigDataResource resource) {
	}

	/**
	 * 当设置 {@link Environment} 的 profiles 时调用。
	 * @param profiles 当前被设置的 profiles
	 */
	default void onSetProfiles(Profiles profiles) {
	}

}
